Overhead door with a plunger assembly having a wear indicator and improved panel construction

Abstract

An overhead door having two tracks each of which is designed to be mounted on the side of an opening in a building. Each track has a script-v shape in cross-section, and a groove or channel that runs along its longitudinal axis. One or more panels are positioned between the tracks and coupled to each other. Each panel has a multiple-layer design that provides superior insulation. At least two plungers are positioned on each panel and each plunger has a first end which is biased in a first position. In the first position, the first end of the plunger rides within the channel of the track. The plungers are designed with a low-friction tip that wears away after repeatedly traveling in the channel of the track. The plungers may be designed to release from the track when the panel on which they are mounted is impacted, to rotate in whole or in part as they travel in a channel of a track, or both.

What is claimed is: 
     
       1. A guide assembly for use in an overhead door mounted in a door opening, the guide assembly comprising: a bracket for being carried by the door;   a pin mounted in the bracket, the pin having a first end and a second end; the first end of the pin including a tip made from a low-friction material subject to observable wear at a predictable rate for indicating the degree of material worn away, the pin adapted to be positioned so that its first end extends beyond the bracket and slides in and frictionally-engages a channel carried in the door opening within which the overhead door is mounted for movement, and further wherein the low-friction material includes an outer layer of a material having a first color and an inner layer of material having a second color that is different from the color of the outer layer of low-friction material, wherein wearing away of the outer layer of low-friction material exposes the inner layer of low-friction material to provide a visual indicator of wear of the tip.   
     
     
       2. A guide assembly as in claim 1, wherein the tip on the first end of the pin comprises a plastic material. 
     
     
       3. A guide assembly as in claim 2, wherein the plastic tip is molded over the first end of the pin. 
     
     
       4. A guide assembly as in claim 1, wherein the first end of the pin is adapted to show through that portion of the tip which has deteriorated due to frictional wear. 
     
     
       5. A guide assembly as in claim 1, wherein the pin mounted for movement in the guide assembly and carries a biasing mechanism for engaging the pin and for biasing the pin into the position where the first end of the plunger extends beyond the bracket. 
     
     
       6. A guide assembly as in claim 1, wherein the pin is fixed in a single position in the bracket. 
     
     
       7. A guide assembly as in claim 1, wherein the pin is rotatable about its longitudinal axis for being rotated by frictional engagement with the channel. 
     
     
       8. A guide assembly as in claim 1, wherein the first end of the pin is rotatable about its longitudinal axis for being rotated by frictional engagement with the channel. 
     
     
       9. A guide assembly as in claim 1, wherein the pin is moveable along its longitudinal axis between a first position, where the first end of the pin extends beyond the bracket, and a second position, where the first end is retracted. 
     
     
       10. A guide assembly as in claim 6 or 9, wherein the first end of the pin includes a plastic tip over it and the first end of the pin shows through the plastic tip when the tip has deteriorated due to frictional wear.